| Value | Category | Cases | |
|---|---|---|---|
| 1 | Less than one year | 10 |
4.8%
|
| 2 | 1-2 years | 26 |
12.6%
|
| 3 | 3-5 years | 15 |
7.2%
|
| 4 | More than 5 years | 156 |
75.4%
|
| Sysmiss | 12670 |